You're using cgminer 3.2.1. It doesn't work with the UART driver (it's what makes it show up as a COM port). Use 3.1.1 and you should be fine.
If you want to use 3.2.1, you'll have to uninstall the UART driver. Rumor has it this doesn't work properly if you have it plugged into a USB 3.0 port. I haven't tried it yet, took too long for me to recover from trying 3.2.0.

M
Just hoping for a quick clarification: By USB 3.0 port do you mean on the computer or where the miner is physically connected. I guess what I'm wondering is if the miners being plugged into a USB 3.0 hub but the hub being plugged into a 2.0 port on the computer makes a difference or if any USB 3.0 connection in the chain is enough to mess it up.
I'm running on 3.1.1 right now, but would love to try 3.2.1 to see if it does reduce the number of HW errors as some have reported. But I don't want to generate unnecessary problems for myself if it is already known not to work.
I had a usb 3.0 4 port plugged into usb 2.0 slot and 3.2.1 worked in linux just fine. I kept getting zombied devices when I assume they would normally get a hardware error. The beauty of 3.2.1 was the miner would go offline then comeback as a different usb miner and start hashing away until the next error but my screen would fill up with zombies. And because of all the zombies going on my hashrate was lower. I am sticking with 3.1.1 for the higher hashrate and I think it just looks better without 15 zombies not hashing away.